1. Field of the Invention
The present invention generally relates to a system for controlling the output-of a musical instrument and, in particular, concerns a system which includes a pressure sensitive control device which is mounted on a musical instrument to allow the player of the instrument to alter various characteristics of the audio output signal of the musical instrument.
2. Description of the Related Art
Electric guitars are extremely popular musical instruments as they can produce a wide range of different sounds when they are used in conjunction with an amplifier. The musician can produce sound signals having a wide range of volume with an electric guitar and the musician can also produce a sound signal from the electric guitar that has a particular sound quality. For example, using the amplifier, the musician can produce a sound signal having a characteristic which varies in volume over time. This characteristic is generally referred to as tremolo. Other types of sound signals that can be produced using an electric guitar include reverberation, vibrato and the like.
The sound signals produced by the guitar are generally adjusted by the musician either changing the settings of dials on the guitar, or by changing settings of dials on an amplifier. Foot pedals are also often used to change the characteristics of the audio signals produced by an electric guitar. It can be appreciated, however, that these devices for changing the characteristics of the sound signals have several disadvantages for the musician.
Specifically, if the musician has to remove his hands from the strings of the guitar to adjust a dial, he cannot continue playing the instrument during that interval. This causes disruptions in the melody that the musician is playing. This problem is somewhat solved by foot pedals which are linked to the amplifier and effectuate changes in characteristics of the audio signal. However, the foot pedals are generally fixedly positioned in one place which requires that the musician also remain in the same place. In many musical performances, the musicians prefer to move around the stage, and their ability to do so is hampered when they have to remain in the proximity of the foot pedals to effectuate changes in the characteristics of the audio signals that they are producing.
One possible solution to this problem has been proposed in U.S. Pat. No. 3,443,018 to Krebs. The Krebs patent discloses an electric guitar wherein compressive rubber resistance elements are built into the neck of the guitar at specific locations. These elements can be used by the musician to change various characteristics of the sound signals, e.g., the volume, by depressing the elements while playing the guitar. However, the guitar in the Krebs patent still suffers from several difficulties.
First, Krebs discloses a guitar wherein the compressive rubber elements are embedded in the neck of the guitar. This requires that the guitar be specially made to facilitate these rubber elements or that the neck of existing guitars be drilled and hollowed to facilitate the rubber elements. Further, the rubber elements are generally small in size and made of a solid piece of rubber. While a solid piece of rubber can be depressed by an individual, the tactile feel of a solid piece of rubber is generally very poor.
In particular, a musician who is depressing one of the elements to change a characteristic of the audio signal in the Krebs guitar will generally not be able to predict ahead of time the exact change of a characteristic of the audio signal. The musician will generally have to wait until the audio signal is produced, and then exert more or less pressure on the element to adjust the signal to have the desired characteristic. Hence, the desired audio signal may not be produced at the desired time or the characteristic may initially be not what the musician intended.
A further difficultly with the Krebs device is that some desired changes in characteristics of audio signals still require the musician to remove his hands from the guitar to effectuate the desired change. For example, if the musician wishes to change the tremolo, e.g., change the frequency of the recurring audio signal having a constant volume, the musician has to remove his hand from the guitar and change a pre-set setting of a dial on the amplifier.
Generally, tremolo settings are pre-set prior to the musician beginning a performance. The musician determines ahead of time the desired frequency of repetition of the audio signal and the desired volume and then, during the performance, engages the tremolo to produce the desired characteristic. If the musician determines during the performance that the settings for a desired effect should be changed, the musician must then stop playing the guitar and change the settings to the new desired settings. It can be appreciated that this significantly limits the flexibility of the musician to change the characteristics of the audio signal while the instrument is being played.
Hence, from the foregoing it is apparent that there is a need in the prior art for a device which allows a musician to change the characteristics of a sound signal produced by a musical instrument without removing his hands from the instrument. To this end, there is a need for an apparatus which allows the musician to know, prior to the production of the resulting sound signal, the changes in a particular characteristic that are going to occur. Further, there is also a need for a system which allows the musician to program multiple different settings for multiple different changes in characteristics ahead of time and then, while playing the instrument, change between the different changes in characteristics.